Phylib uses workqueues for multiple purposes. There is no real dependency of
scheduling these on the cpu which scheduled them.
On a idle system, it is observed that and idle cpu wakes up many times just to
service this work. It would be better if we can schedule it on a cpu which isn't
idle to save on power.
By idle cpu (from scheduler's perspective) we mean:
- Current task is idle task
- nr_running == 0
- wake_list is empty
This patch replaces the schedule_work() and schedule_delayed_work() routines
with their queue_[delayed_]work_on_any_cpu() siblings with system_wq as
parameter.
These routines would look for the closest (via scheduling domains) non-idle cpu
(non-idle from schedulers perspective). If the current cpu is not idle or all
cpus are idle, work will be scheduled on local cpu.
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: netdev@xxxxxxxxxxxxxxx
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
drivers/net/phy/phy.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index 298b4c2..a517706 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -439,7 +439,7 @@ void phy_start_machine(struct phy_device *phydev,
{
phydev->adjust_state = handler;
- schedule_delayed_work(&phydev->state_queue, HZ);
+ queue_delayed_work_on_any_cpu(system_wq, &phydev->state_queue, HZ);
}
/**
@@ -527,7 +527,7 @@ static irqreturn_t phy_interrupt(int irq, void *phy_dat)
disable_irq_nosync(irq);
atomic_inc(&phydev->irq_disable);
- schedule_work(&phydev->phy_queue);
+ queue_work_on_any_cpu(system_wq, &phydev->phy_queue);
return IRQ_HANDLED;
}
@@ -682,7 +682,7 @@ static void phy_change(struct work_struct *work)
/* reschedule state queue work to run as soon as possible */
cancel_delayed_work_sync(&phydev->state_queue);
- schedule_delayed_work(&phydev->state_queue, 0);
+ queue_delayed_work_on_any_cpu(system_wq, &phydev->state_queue, 0);
return;
@@ -966,7 +966,8 @@ void phy_state_machine(struct work_struct *work)
if (err < 0)
phy_error(phydev);
- schedule_delayed_work(&phydev->state_queue, PHY_STATE_TIME * HZ);
+ queue_delayed_work_on_any_cpu(system_wq, &phydev->state_queue,
+ PHY_STATE_TIME * HZ);
}
static inline void mmd_phy_indirect(struct mii_bus *bus, int prtad, int devad,
--
1.7.12.rc2.18.g61b472e
--
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